Post on 02-Feb-2016
description
transcript
The CMS muon system
Borislav Pavlov
(University of Sofia “St. Kliment Ohridski”)
for
the CMS Collaboration
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Introduction
Introduction CMS Muon System DT CSC RPC Moun Trigger Summary
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
CMS: design & construction
Muon System
CMS
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
System Conditions & Requirements
Barel < 1.3
Particle rates < 10 Hz/cm2
Low Magnetic field
Endcap 0.9 < < 2.4
Particle rates 100-1000 Hz/cm2
Magnetic field
Uniform axial > 3 T in ME1/1
Highly non-uniform radial field
Up to 1 T in ME1/2
Muon identification Muon Trigger
Unambiguous BX identification Trigger single and multimuon with well
defined pt thresholds few GeV to 100 GeV
Muon momentum measurement Charge assignment correct to 99%
confidence level up to 7 TeV Momentum resolution
Stand alone
dpt/pt = 8 - 15% at pt = 10 GeV
dpt/pt = 20 - 40% at pt = 1 TeV Global
dpt/pt = 1 - 1.5% at pt = 10 GeV
dpt/pt = 6 - 17% at pt = 1 TeV
System Conditions Requirements
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Reduced RE system|| < 1.6
1.6
ME4/1 restored
MB1
MB2
MB3
MB4
ME1ME2 ME3
¼ longitudinal slice
CMS Muon System
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Requirements
Resolution (per station)
Position R : 100 m Z : 150 m Angle: 1 mradBX identification Efficiency
>98% per station
Drift Tubes - DT Cathode Strip Chambers - CSC
Spatial resolution () (per station) 75 m ME1/1 and ME1/2 150 m for the others
(At the trigger level < 2mm)Correct BX identification
> 92% per chamber ( 99% global)
Trigger Track Efficiency >99 % per chamber
BARREL ENDCAP
Resistive Plate Chambers - RPC
(Dedicated Trigger Detector) Good timing : Resolution < 3ns (RMS), 98% within a 20ns window Good Rate capability Low cluster size High efficiency > 90% per chamber ( 95% global) r resolution ~ 1cm
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Drift Tube Chambers
MylarMylar
Electrode Electrode StripStrip
Cathode Al Strips
Wire
42mm
13 mm
GASGAS: Ar/CO2 (85/15))
HV: HV: Wires 3600 V Strips 1800 V I-beams -1200 V
Tmax: Tmax: 380 ns Single Wire Single Wire 100m Drift Velocity :Drift Velocity : ~ 55m/ns Resolution : Resolution : < 300 m 150m
4 Layers = 1 4 Layers = 1 SuperlayerSuperlayer (SL) (SL)
Independent SubunitIndependent Subunit
(Gas tightness, HV, Front End)
SL SL
Honeycomb SL
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
DT Local trigger - Bunch Track Identifier (BTI)
Based on meantime technique
MT is independent on the track angle and position
MT1 = 0.5 * (T1 + T3) + T2MT2 = 0.5 * (T2 + T4) + T3
Signals are shifted in registersBTI looks for coincidence every clock period
hits in ≥ 3 planes At a time T=Tmax after muon crossing the drift times are aligned i.e. the hits form an image of the muon track
Allows effective bunch crossing identification
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Barrel Muon DT
1
4
2
35
6
7
89 10
11
12
60 MB1 3SL 2 RPC ~2.0 x 2.54 m2 960kg60 MB2 3SL 2 RPC ~2.5 x 2.54 m2 1200kg60 MB3 3SL 1 RPC ~3.0 x 2.54 m2 1300kg
40 MB4 2SL 1 RPC ~4.2 x 2.54 m2 1800kg
10 MB1 2SL 1 RPC 10 MB2 2SL 1 RPC10 MB3 2SL 1 RPC
The Barrel Muon system comprises 250 chambersIn 7 flavors for 5 wheels Total 1700 m2
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Production sitesCIEMAT AACHEN
LEGNAROTORINODT Production
Sites
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Cosmic Event in a CMS sector
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Magnetic field = 1T Cosmic muon trajectory in the barrel DTs
http://cms.cern.ch/
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Cathode Strip Chambers (CSC)
Gas:Ar(40%) + CO2 (50%) + CF4(10%)
Gas gap 9.5mm
Wire spacing ~3mm
HV wires ~ 3.6 kV
Trapezoidal Chambers (100 or 200 in ), 6 layers
Radial cathode strips – measure (75-150 m)
Wires orthogonal to strips
Precise timing measurement (BX) - ~4.5 ns
Coarse measurement of the radial position (16-54 mm)
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
CSC
ME1/1 –special design
Inserted in endcap
Calorimeter support
Outer section of 4’th station staged
6 planes per chamber
468 chambers
6000 m2 sensitive area
2 Million wires
220 K cathode channels
1 chamber ~ 1000 readout chanels
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
PNPI – 114 assembled
DubnaFNAL – 148 assembled
IHEP – 148 assembled
Dubna – 72 assembled
Chamber with on-board electronics
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
ISR FAST Site
Final Testing before installation at SX5
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
YE+1 YE-1
14 June, 2006CSCs on YE+1 and YE-1
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Cosmic Ray
using test pulses and cosmic rays
First particles detected by installed “CMS” subsystem!!
Chamber commissioning at SX5
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Resistive Plate Chambers
Resistive PlatesResistive Plates – – bakelite with bulk bakelite with bulk resistivity (2 ± 1).resistivity (2 ± 1).10101010ΩΩcmcm
Gas gapGas gap ( (2mm ± 202mm ± 20μμm widem wide) )
Gas mixtureGas mixture, containing , containing
96% C96% C22HH22FF44(Freon), (Freon),
3,5 % isobutan, SF3,5 % isobutan, SF66 – 0,5 % – 0,5 %
Graphite electrodesGraphite electrodes with resistivity with resistivity 300 k300 kΩΩ / cm / cm
Insulating PET filmInsulating PET film ( (0.3 mm thick0.3 mm thick))
Detecting copper stripsDetecting copper strips
4040μμm thick,2–4 cm wide and 1250 m thick,2–4 cm wide and 1250 mm longmm long
Spacers (Spacers (cylinders withcylinders with
diameter 10 mm and height 2mmdiameter 10 mm and height 2mm))
Copper shielding Copper shielding
Linseed oil treatmentLinseed oil treatment
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
RPC - Principle of Action
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
CMS RPC
Fast detectors for the first level trigger of the experiment
Considerably good space resolution
Able to work in areas with background ~ 10 3 Hz/cm 2
Price – as low as possible
RequirementsTime resolutionTime resolution ≤ 1.8 ns≤ 1.8 ns
(98 % within 20 ns)(98 % within 20 ns)
EfficiencyEfficiency > 95 %> 95 %
Rate capabilityRate capability ≤ 1kHz/cm2≤ 1kHz/cm2
•Average cluster sizeAverage cluster size < 2 strips < 2 strips •Number of streamersNumber of streamers < 10%< 10%•Operation plateauOperation plateau > 300V> 300V•Power consumptionPower consumption 2-3 W/m2-3 W/m22
•Operational voltage 8.5 –10 kVOperational voltage 8.5 –10 kV
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Main Barrel RPC Types
RB4
RB3
RB2
RB1
Length: 2.455 m Width: 1.5, 2.0 , 2.5 mPitch: 40.8, 40.6, 41.0 mm# Strips for Gap: 48, 36, 48, 60
Left Right
Left Right
Out
Out
In
In
Width: 1.48 mPitch: 34.8 mm# Strips for Gap: 42
Width: 1.5, 2.0 , 2.5 mPitch: 27.3, 29.3 mm# Strips for Gap: 84, 90
Width: 1.5, 2.0 , 2.5 mPitch: 22.7, 24.3 mm# Strips for Gap: 84, 90
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Barrel RPC Production
GT
HT
Bari
Pavia SofiaChambers production and quality certification involve several steps.
Chambers production and quality certification involve several steps.
ISR
Chamber test Sites
Double gap
GTSingle gap
RB1 in PaviaRB2 & RB4 in BariRB3 in Sofia (& Bari)
Chamber assembling Sites 120 RB1 at HT240 RB2 and RB4 at GT120 RB3 in Sofia (& Bari)
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
RPC Production Sites
Bari Sofia
Pavia
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
RPC tests at ISR
ISR RPC storage and test area
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Installation of DT and RPC
At SX5
Installation in the CMS Detector
Started in June
At ISR
Coupling RPC to DT
Fast test
Transportation to SX5( CMS surface hall)
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Cosmic event in the RPCs
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
RE1/1
RE1/2
RE1/3
RE2/1
RE2/2
RE2/3
RE3/1
RE3/2
RE3/3
RE4/1
RE4/2
RE4/3
No. of chambers 36*2 36*2 36*2 18*2 36*2 36*2 18*2 36*2 36*2 18*2 36*2 36*2
ChinaChina
KoreaKorea
PakistanPakistan
Gap production
Korea
Gap production
Korea
Front-end electronics
Pakistan
Front-end electronics
Pakistan
CERN
Project Co-ordination
ISR Assembly Station
CERN
Project Co-ordination
ISR Assembly Station
Endcap RPC
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
RPC Production Sites
Korea Pakistan
ISR Lab
Test of first chambers
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Muon Trigger
6th BPU Conference B. Pavlov Istanbul, 22-26 August 2006
Summary
CMS Muon System – big international project - 3 Continents
DT ChambersDT production ended (266 out of 250)
Delivered to CERN - 262
Installed - 146
CSC ChambersProduction finished (496 out of 468 CSCs)
Delivered to CERN – 495
Installed - 432
RPC Chambers460 (out of 480) barrel RPCs assembled.
End of production - December.
Delivered to CERN – 380
Installed - 278
Endcap RPC – YE+1 and YE+2 installed
Endcap RPC - YE+3 and YE-1 will be installed until the end of the year
Magnet test and Cosmic runs are going now